This study was initiated during a successful test of the Coolside flue gas desulfurization technology at Ohio Edison`s Edgewater generating station in 1991. Coolside is a lime duct technology which is installed on the downstream side of the last heat exchanger. As tested by Ohio Edison, it also employs an alkali reagent, in this case NaOH, to enhance sulfur capture. The overall goal of this study was to develop sufficient chemical and physical data to insure the environmentally safe disposal of the material. This final report summarizes the important aspects of the project, but it does not present all of the data that was produced. Further details may be found in the monthly and quarterly reports that were filed with the Morgantown Energy Technology Center. This report is organized into six chapters which present the important conclusions of the principal areas of investigation.